The drive is taking place as part of the world project "Let's do it!" and the World Cleanup 2012 drive. Croatia joined in for the first time. Every county, more than 70 towns and municipalities and more than 30,000 volunteers are taking part in it, said campaign manager Helena Traub.
President Josipovic took part in the cleanup of an illegal dumping site together with the army, students, citizens and volunteers from Slovenia.
"Ecology is Croatia's future. We certainly can't do everything overnight, but we must realise that the ecological approach to life is fundamental for the health of Croatia, the health of our people, and for economic development," he said, recalling that Croatia based a big part of its development strategy on tourism, health food and agriculture.
"We can't count on health food and tourism with this garbage. Therefore, let's do everything for Croatia to be green," said Josipovic.
Asked by the press about factories on the coast, he said people were very sensitive about that.
We should have factories, but they must have high protection standards, state-of-the art filters and plants, he said.
Asked if he was ecologically aware, Josipovic said he tried to be, adding that everyone should refrain from illegally dumping garbage, respect standards and be informed about the damage of polluting the environment.
He said the regulations being drawn up on garbage disposal were a step in the right direction, as they would not only protect the environment but also be good for the economy.
Milanovic, Environment Minister Mirela Holy, Labour Minister Mirando Mrsic and Justice Minister Orsat Miljenic took part in the cleanup of another illegal dumping site in Zagreb.
Responding to questions from the press, Milanovic said he thought he was an ecologically aware prime minister.
He said local communities' efforts were futile if people continued to illegally dispose of garbage, adding that it was a matter of education and patience.
He said today's drive was an attempt to raise awareness of something important.
Holy said many public figures had supported the drive, which was important, as its goal was to clean up the illegal garbage sites as well as warn the public against dumping garbage in nature.
Traub said the drive was taking place also in Latvia, Lithuania, Spain, Austria, Russia, and California, adding that more than 90 countries had joined in the World Cleanup drive to date.
Also today, Earth Day 2012, Josipovic and Holy attended the opening of the "dm green city project 2012" in downtown Zagreb which, in this International Year of Sustainable Energy for All, is aimed at raising citizens' eco-awareness and responsibility in everyday life.
Josipovic said the project was "something really valuable," adding that he was pleased that the young were eco-aware, "that they know that we should take care of the environment and our planet Earth."
Holy wished everyone a better and more preserved environment, saying it was a prerequisite for all Croatian citizens.